Cellular telephones have become ubiquitous in today's society, playing an important roll in many areas of daily life. The technology has reached the point where cellular telephones are manufactured with the same features as regular telephones, including speed dial and number recall. A user such as a physician or salesperson has the capability to be constantly in communication without having to stop at pay telephones or use specialized communication equipment. Power conservation is a constant concern for the user. As cellular telephones are generally either self-contained or mounted in a vehicle, however, a user must, particularly in the case of self-contained units, maintain sufficient power to ensure that the telephone will work when it is needed. The most efficient means of power conservation is to turn the telephone on only when the user wishes to send or receive calls. Another consideration is that the ability of the outside world to make contact no matter where a person is may be more than the user bargained for--so long as the telephone is activated the user will receive calls. The impact of this exposure can range from mere inconvenience to significant annoyance at the unwanted intrusion. There is no convenient method for controlling the use of air time--the only sure method of preventing unwanted incoming calls is to turn off the telephone. If, however, the user wants the telephone turned on for only certain time periods, the user must constantly remember to turn their cellular telephone on when they want to be able to receive calls and off when they do not want incoming calls or when they want to conserve battery life. What is needed is a better way to schedule cellular telephone availability.
As each user's communication requirements vary, so do the periods of time which each user wants or needs their telephone activated. Some need to have their telephone on all day every day. Others only activate their telephone when they wish to make outgoing calls. The majority of cellular telephone users, however, have particular periods of the day or week during which they wish to send or receive calls. Some of these users need additional telephone functions such as call forwarding or call waiting available at the same or different times. For example, a person may not want to receive calls on the cellular telephone or deplete its power resources while they are at work or home. However, when they cannot be reached by a regular telephone, such as when they are driving to or from work, the user may then want to be able to receive calls. A user who wishes to activate a cellular telephone during specific periods of the day must remember to activate and deactivate the telephone. What is needed is a convenient way to ensure a cellular telephone is ready to send and receive calls, or perform other of the cellular telephone's functions, according to a particular user's needs.